1. Field of the Invention
The present invention relates to child and infant enclosure structures (e.g., playpens, cribs, play yards, bassinets and other similar enclosures). In particular, the present invention relates to child and infant enclosure structures made of a selected composite tubing. Preferably, besides being made from this selected composite tubing, the enclosure structures have a floor structure made of a selected construction, and have certain hinge assemblies for folding and storing these enclosure structures.
2. Brief Description of the Art
Most infant's and children's playpens and cribs are currently constructed using steel, aluminum, or other metal tubular frames. These materials, in their usual form, provide the requisite strength and stiffness required to satisfy the physical demands of the application. The use of tubing, as described by the prior art, allows for a foldable design that is both practical and yet employs a minimal use of the specified structural materials. Recent examples of portable or foldable playpens and cribs include the following:
U.S. Pat. No. 3,800,341 (Davanzo) teaches a portable and collapsible playpen or crib made of plastic construction.
U.S. Pat. No. 4,491,992 (Frederick Whitman) describes a convertible baby crib and playpen. Specifically, this reference discloses an adjustable-sized, readily assembled and readily disassembled baby crib made up of a series of plastic tube sections and plastic tube fittings.
U.S. Pat. No. 4,575,224 (Saint) teaches a foldable playpen having frame portions and platform sections which pivot in opposite directions as leg frames move between extended and collapsed positions.
U.S. Pat. No. 4,688,280 (Kohus et al.) describes a foldable playpen having a base frame including a central hinged byfold hub attached to form horizontal floor support bars, each of which, in turn, are connected to a vertical corner frame member.
U.S. Pat. No. 4,703,525 (Shamie) is directed to a foldable playpen frame wherein four floor support members are connected together in a central socket hinge means. The floor members are also connected at their other ends to vertical upright members are connected to two pairs of cross members.
U.S. Pat. No. 4,710,049 (Chang) describes a foldable infant play yard containing a specifically defined safety hinge covered with padding material to prevent injury to the infant.
U.S. Pat. No. 4,739,527 (Kohus et al.) teaches a foldable playpen assembly that contains a central hub under the floor of playpen linked to at least four vertical support legs spaced outwardly from the hub. The linkage between the hub and the vertical support legs being adapted to maintain the legs in a first expanded spaced array when in use and to be moved to second contracted compact array in which the legs are much closer to the central hub when being stored or transported.
U.S. Pat. No. 4,811,437 (Dillner et al.) is directed to a foldable play yard comprising a foldable upper frame assembly and a foldable lower frame assembly with corner legs freely interconnecting to the upper and lower frame assemblies. The upper frame assemblies contain pairs of in-line upper side rails which are pivotally coupled at their outer ends to adjacent lower rail connecting members and at their inner ends to a medial rail connecting member. The medial rail connecting mechanism either houses a hand releasable latch mechanism or a rotatable latch mechanism for latching and releasing the said rail pairs into or from the in-line position. The lower frame assembly comprises a unitary central hub member, hub legs each pivotable coupled at one end portion thereof to said hub member and pivotally coupled at an opposite end position thereof to a lower frame assembly corner leg connecting members. When the play yard is erected and in use, the hub legs and side rails maintain the corner legs and side rails upstanding in a spread configuration. When the play yard is in storage or being transported, the hub legs and side rails are collapsed and draw the corner legs towards the hub member and into a compact configuration.
U.S. Pat. No. 4,877,875 (Shamie et al.) is directed to a foldable playpen having a plurality of floor supports connected at a central hub means. The plurality of the floor supports connected at their other ends to lower corner hinge means. These lower corner hinge means also connected to upright support means. The upper ends of said upright support means are connected to a plurality of cross-members, each connected between adjacent pairs of uprights. At least some of said cross-members having bending means permitting bending of said at least some of said cross-members. U.S. Pat. No. 4,985,948 (Mariol) teaches a foldable play yard comprising the combination of (a) an essentially rectangular upper support formed of four pairs of rods each centrally coupled by a hinge, (b) an essentially rectangular lower support formed of four pairs of rods, each centrally coupled by a hinge; (c) four vertical rails interconnecting the corners of the upper and lower supports; and (d) a unitive fabric assembly comprising four vertically disposed panels each coupled between a pair of rods of the upper support and lower support and adjacent vertical rails, the fabric assembly also including a lower horizontal panel stitched to the vertically disposed panels and coupled between the rods of the lower rectangular support.
U.S. Pat. No. 5,081,723 (Saunders) teaches a playpen with detachable sides. This patent states that the sides and other components of this invention may be made from plastic, lightweight metal, fiberglass, wood, or other suitable materials and the body or webbing may be made from mesh such as vinyl-coated wire mesh, fabric, cloth, plastic, or fiber mesh.
U.S. Pat. No. 5,197,154 (Shamie) describes a foldable playpen containing a lower frame assembly including first and second auxiliary lower floor support legs, an inverted U-shaped bracket which pivotally connects inner ends of the lower auxiliary floor support legs together for movement between the first in-line position and a second folded position where the auxiliary lower floor support legs are substantially parallel with each other, and four lower floor support rails having inner and outer ends, the inner end of each lower floor support rail being pivotally connected to a substantial mid-point of a respective lower auxiliary floor support leg by means of a bracket plate for movement in a second plane substantially traverse to the first plane.
U.S. Pat. No. 5,211,498 (Huang et al.) describes a specifically designed folding joint for a foldable play yard.
U.S. Pat. No. 5,228,154 (Brevi et al.) teaches a foldable cot or playpen having a shaped lower support frame.
U.S. Pat. No. 5,239,714 (Huang) teaches a foldable playpen structure having a floor assembly consisting of (a) four bars respectively pivotally linking to lower corner connections and (b) a central joint comprising two pivotally joined halves wherein one half pivotally to two of the bars while the remaining half pivotally links to the remaining two bars; and an auxiliary foot pivotally linked to one of the halves so that said auxiliary foot is retained vertical for supporting said bars when said halves are laid in the same horizontal plane.
U.S. Pat. No. 5,243,718 (Shamie) teaches a foldable playpen having a specifically designed securing means for attaching rail sections in the upper frame and a lower frame assembly including a central hub having two sections hinged together.
U.S. Pat. Des. No. 304,523 (Dillner et al.) describes a foldable play yard having a floor frame assembly having a central hub and six floor-supporting legs connected to said hub.
Consumer Reports (May, 1993) page 288 lists several considerations when buying a portable crib. Those include light weight; ease of assembly and disassembly; ease of storing and transporting; and lack of sharp edges, finger entrapments or small parts.
The standard methods of constructing metal tubular playpens and cribs involve cutting the metal tubing the required lengths, punching out the required holes for fittings, and then fastening the tubing together in a design that provides for the convenient folding, storage, and transportation of the playpen.
The use of metal tubing currently infers a high degree of quality that other materials such as plastics do not convey. Separately, the use of metal tubing, versus metal plates or solid rods or other solid metal forms, allows for some weight minimization that would not otherwise be possible and also provides for playpen or crib designs that can be easily and conveniently folded, stored, and transported.
Unfortunately, the use of metal tubing in a playpen or crib results in a still relatively heavy product. The use of metal tubing also requires the use of connective fittings and hinges that may themselves constructed of metal or partially metal parts. These add to the weight of the product and make it less convenient to fold, store, and transport. Metal parts also require complicated coatings or treatments to minimize or prevent corrosion, even under ambient humidity conditions. Corrosion results in weakened parts which may unexpectedly fail. These corroded surfaces and chemical coatings may also be highly toxic to the infants. Such pretreatments necessary to coat the metal are also time intensive and relatively expensive, thus lengthening the production time and cost of the product.
Thermoplastic and thermoset plastic tubes of similar dimensions to these metal tubes have alternatively been considered for this use. It is noted that the use of thermoset or thermoplastic tubing or rods would allow for weight minimization that would not otherwise be possible with metal parts. Additionally, the use of thermoset or thermoplastic tubing or rods versus rigid thermoset or thermoplastic plates, mesh or other forms also would provide for playpen or crib design that could be easily and conveniently folded, stored, and transported. However, most economical plastics do not possess the required stiffness to maintain long term dimensional stability. Under the loads required by ASTM Test Method F406 for playpens, the most economical thermoplastics will deflect and even permanently deform or break. Such properties are not acceptable and pose a significant risk to an infant. Specifically, their relatively poor physical strength and stiffness require thicker walled tubes or even solid rods. Such tubes or rods dramatically increase the weight of the product. Additionally, the use of plastics in general also infer a lack of quality or "cheapness" that further detracts from their use as primary structural materials in such products. Moreover, while plastics do not corrode and do not usually require the use of coatings or pretreatments, coating plastics is time-intensive and relatively complicated and again causes more expensive and longer production times.
Certain composite materials have properties that preclude their use for playpen or crib applications. For example, ceramic-metal and wood-thermoset plastic composites have the disadvantage of their relative heavy weight. In this regard, it is noted that U.S. Pat. No. 3,916,802 states that an infant dressing table " . . . may be constructed of wood or fiber composite materials". It is also noted the reference does not provide any teaching of any preferred type of fiber composite material of the present invention. Glass fiber reinforced polyester matrix composites are an improvement of the aforementioned composites, but these latter materials are relatively thick and bulky.
A significant benefit would be achieved by employing a material that did not require substantially thickening or ribbing to achieve the required strength and rigidity. It would be even better still if a material could be found which could be thinner than unreinforced plastic in the structural components of playpens and cribs.
Based upon the above, a need clearly exists for a playpen design that employs lightweight, durable, strong, stiff, noncorroding parts that feel and sound like metal, and allow for a design that is itself lightweight, of consistent quality, safe, durable and easily folded, stored, and transported, all at a relative low cost. The previously mentioned prior art does not provide for the combination of all of the above properties. Such an invention would be highly beneficial to the users of playpens and cribs. It has now been found that the various aspects of the present invention meet this need.